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1// SPDX-License-Identifier: GPL-2.0+2/*3 * Watchdog driver for DA9063 PMICs.4 *5 * Copyright(c) 2012 Dialog Semiconductor Ltd.6 *7 * Author: Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>8 *9 */10 11#include <linux/kernel.h>12#include <linux/module.h>13#include <linux/watchdog.h>14#include <linux/platform_device.h>15#include <linux/uaccess.h>16#include <linux/slab.h>17#include <linux/i2c.h>18#include <linux/delay.h>19#include <linux/mfd/da9063/registers.h>20#include <linux/mfd/da9063/core.h>21#include <linux/property.h>22#include <linux/regmap.h>23 24/*25 * Watchdog selector to timeout in seconds.26 * 0: WDT disabled;27 * others: timeout = 2048 ms * 2^(TWDSCALE-1).28 */29static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };30static bool use_sw_pm;31 32#define DA9063_TWDSCALE_DISABLE 033#define DA9063_TWDSCALE_MIN 134#define DA9063_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1)35#define DA9063_WDT_MIN_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MIN]36#define DA9063_WDT_MAX_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MAX]37#define DA9063_WDG_TIMEOUT wdt_timeout[3]38#define DA9063_RESET_PROTECTION_MS 25639 40static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)41{42 unsigned int i;43 44 for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {45 if (wdt_timeout[i] >= secs)46 return i;47 }48 49 return DA9063_TWDSCALE_MAX;50}51 52/*53 * Read the currently active timeout.54 * Zero means the watchdog is disabled.55 */56static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063)57{58 unsigned int val;59 60 regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val);61 62 return wdt_timeout[val & DA9063_TWDSCALE_MASK];63}64 65static int da9063_wdt_disable_timer(struct da9063 *da9063)66{67 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,68 DA9063_TWDSCALE_MASK,69 DA9063_TWDSCALE_DISABLE);70}71 72static int73da9063_wdt_update_timeout(struct da9063 *da9063, unsigned int timeout)74{75 unsigned int regval;76 int ret;77 78 /*79 * The watchdog triggers a reboot if a timeout value is already80 * programmed because the timeout value combines two functions81 * in one: indicating the counter limit and starting the watchdog.82 * The watchdog must be disabled to be able to change the timeout83 * value if the watchdog is already running. Then we can set the84 * new timeout value which enables the watchdog again.85 */86 ret = da9063_wdt_disable_timer(da9063);87 if (ret)88 return ret;89 90 usleep_range(150, 300);91 regval = da9063_wdt_timeout_to_sel(timeout);92 93 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,94 DA9063_TWDSCALE_MASK, regval);95}96 97static int da9063_wdt_start(struct watchdog_device *wdd)98{99 struct da9063 *da9063 = watchdog_get_drvdata(wdd);100 int ret;101 102 ret = da9063_wdt_update_timeout(da9063, wdd->timeout);103 if (ret)104 dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n",105 ret);106 107 return ret;108}109 110static int da9063_wdt_stop(struct watchdog_device *wdd)111{112 struct da9063 *da9063 = watchdog_get_drvdata(wdd);113 int ret;114 115 ret = da9063_wdt_disable_timer(da9063);116 if (ret)117 dev_alert(da9063->dev, "Watchdog failed to stop (err = %d)\n",118 ret);119 120 return ret;121}122 123static int da9063_wdt_ping(struct watchdog_device *wdd)124{125 struct da9063 *da9063 = watchdog_get_drvdata(wdd);126 int ret;127 128 /*129 * Prevent pings from occurring late in system poweroff/reboot sequence130 * and possibly locking out restart handler from accessing i2c bus.131 */132 if (system_state > SYSTEM_RUNNING)133 return 0;134 135 ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,136 DA9063_WATCHDOG);137 if (ret)138 dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n",139 ret);140 141 return ret;142}143 144static int da9063_wdt_set_timeout(struct watchdog_device *wdd,145 unsigned int timeout)146{147 struct da9063 *da9063 = watchdog_get_drvdata(wdd);148 int ret = 0;149 150 /*151 * There are two cases when a set_timeout() will be called:152 * 1. The watchdog is off and someone wants to set the timeout for the153 * further use.154 * 2. The watchdog is already running and a new timeout value should be155 * set.156 *157 * The watchdog can't store a timeout value not equal zero without158 * enabling the watchdog, so the timeout must be buffered by the driver.159 */160 if (watchdog_active(wdd))161 ret = da9063_wdt_update_timeout(da9063, timeout);162 163 if (ret)164 dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n",165 ret);166 else167 wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)];168 169 return ret;170}171 172static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action,173 void *data)174{175 struct da9063 *da9063 = watchdog_get_drvdata(wdd);176 struct i2c_client *client = to_i2c_client(da9063->dev);177 union i2c_smbus_data msg;178 int ret;179 180 /*181 * Don't use regmap because it is not atomic safe. Additionally, use182 * unlocked flavor of i2c_smbus_xfer to avoid scenario where i2c bus183 * might previously be locked by some process unable to release the184 * lock due to interrupts already being disabled at this late stage.185 */186 msg.byte = DA9063_SHUTDOWN;187 ret = __i2c_smbus_xfer(client->adapter, client->addr, client->flags,188 I2C_SMBUS_WRITE, DA9063_REG_CONTROL_F,189 I2C_SMBUS_BYTE_DATA, &msg);190 191 if (ret < 0)192 dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n",193 ret);194 195 /* wait for reset to assert... */196 mdelay(500);197 198 return ret;199}200 201static const struct watchdog_info da9063_watchdog_info = {202 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,203 .identity = "DA9063 Watchdog",204};205 206static const struct watchdog_ops da9063_watchdog_ops = {207 .owner = THIS_MODULE,208 .start = da9063_wdt_start,209 .stop = da9063_wdt_stop,210 .ping = da9063_wdt_ping,211 .set_timeout = da9063_wdt_set_timeout,212 .restart = da9063_wdt_restart,213};214 215static int da9063_wdt_probe(struct platform_device *pdev)216{217 struct device *dev = &pdev->dev;218 struct da9063 *da9063;219 struct watchdog_device *wdd;220 unsigned int timeout;221 222 if (!dev->parent)223 return -EINVAL;224 225 da9063 = dev_get_drvdata(dev->parent);226 if (!da9063)227 return -EINVAL;228 229 wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL);230 if (!wdd)231 return -ENOMEM;232 233 use_sw_pm = device_property_present(dev, "dlg,use-sw-pm");234 235 wdd->info = &da9063_watchdog_info;236 wdd->ops = &da9063_watchdog_ops;237 wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT;238 wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT;239 wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS;240 wdd->parent = dev;241 wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS;242 243 watchdog_set_restart_priority(wdd, 128);244 watchdog_set_drvdata(wdd, da9063);245 dev_set_drvdata(dev, wdd);246 247 wdd->timeout = DA9063_WDG_TIMEOUT;248 249 /* Use pre-configured timeout if watchdog is already running. */250 timeout = da9063_wdt_read_timeout(da9063);251 if (timeout)252 wdd->timeout = timeout;253 254 /* Set timeout, maybe override it with DT value, scale it */255 watchdog_init_timeout(wdd, 0, dev);256 da9063_wdt_set_timeout(wdd, wdd->timeout);257 258 /* Update timeout if the watchdog is already running. */259 if (timeout) {260 da9063_wdt_update_timeout(da9063, wdd->timeout);261 set_bit(WDOG_HW_RUNNING, &wdd->status);262 }263 264 return devm_watchdog_register_device(dev, wdd);265}266 267static int __maybe_unused da9063_wdt_suspend(struct device *dev)268{269 struct watchdog_device *wdd = dev_get_drvdata(dev);270 271 if (!use_sw_pm)272 return 0;273 274 if (watchdog_active(wdd))275 return da9063_wdt_stop(wdd);276 277 return 0;278}279 280static int __maybe_unused da9063_wdt_resume(struct device *dev)281{282 struct watchdog_device *wdd = dev_get_drvdata(dev);283 284 if (!use_sw_pm)285 return 0;286 287 if (watchdog_active(wdd))288 return da9063_wdt_start(wdd);289 290 return 0;291}292 293static SIMPLE_DEV_PM_OPS(da9063_wdt_pm_ops,294 da9063_wdt_suspend, da9063_wdt_resume);295 296static struct platform_driver da9063_wdt_driver = {297 .probe = da9063_wdt_probe,298 .driver = {299 .name = DA9063_DRVNAME_WATCHDOG,300 .pm = &da9063_wdt_pm_ops,301 },302};303module_platform_driver(da9063_wdt_driver);304 305MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");306MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");307MODULE_LICENSE("GPL");308MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);309